I was reading a book which I only realized was set in the UK and written by a UK author after they started mentioning things like "boots" without meaning footwear and "Mum" for a maternal figure :) (the punctuation style and complete lack of a setting for a long while had me thinking it was set in the US for some reason...) and since then I've become hypersensitive to any and all BritEnglish peculiarities in the book.
One that stood out to me, however, was a sentence that went along the lines of, "It was a beautiful weapon, and it fitted his hand nicely."
For me, "fit" in the past tense is still "fit", as in, "The puzzle piece fit perfectly." I would only use "fitted" in the passive voice or as an adjective, I think ("The dress was fitted snugly around the form." or "A well-fitted pair of pants" -- mostly to do with clothes, as you can see), and even then it still has a different meaning from "fit" as the passive form :/
I'm a bit confused as to what this means, only that I would never use "fitted" in the way it was used in the book--as the past tense of "fit". I'm a native US English speaker, though, and wondering if this is something unique to UK English (or unique to non-US English even?)